Category Archives: Research

We are Brandeis science: Madelen Díaz

There is no rule that says scientists have to look or act a certain way. Scientists can be funny and outgoing, athletic and artistic. They come from all different backgrounds and have all different interests. At Brandeis, our scientists are as diverse as the groundbreaking research they engage in. This on-going series is inspired by This is What a Scientist Looks Like

This post was written by Madelen Díaz, PhD student in professor Michael Rosbash’s lab. 

The music of the mind

Madelen Diaz
Madelen Diaz

Where are you from?

I was born and raised in Miami, Fla. after my parents emigrated from Cuba.

What do you research?

I currently research the neuronal circuitry responsible for circadian rhythm in the fruit fly (Drosophila melanogaster). Why do we use the fruit fly to study circadian rhythm? Fruit flies sleep at night and even sleep the siesta during the afternoon. Several of the molecular proteins responsible for these behavioral oscillations are conserved across species. We use complex genetic tools, behavioral assays, and several imaging techniques to see how these circadian neurons coordinate with each other to produce their active/sleep cycle throughout the day.

What is your biggest passion outside of science? 

My passion outside of science has always been classical piano. I’ve been playing since I was 6 years old. There is something incredibly relaxing about immersing yourself into the music that you forget that ever-growing “to-do” list.

How do you define discovery, and how does it make you feel?

I would term discovery as obtaining an unexpected or controversial result. It’s very exciting thinking of the possibilities of a new discovery and how this can potentially contribute to the “big picture.” It can also be nerve-wracking because of the uncertainty of not knowing what to do next or where to look. The most difficult part of graduate school is to continue working through all of the uncertainty.

What do you do to unwind, after a long day at the lab?

After a long day in the lab, I most commonly relax by baking desserts or playing piano. On weekends, I like to go out salsa dancing or traveling New England.

Ready for a smashing success

After two-years of upgrades and repairs, the Large Hadron Collider is back in the particle smashing business — this time at double the energy of its first run. Today, researchers at CERN began recording data from the highest-energy particle collisions ever achieved on Earth, and began a new set of experiments that will shed light on a new realm of physics.

I spoke with professor Gabriella Sciolla about the restart and the frontier of physics.

What are the biggest discoveries physicists hope to make in the coming year with this new, improved experiment?

The big goal is to search for what we call “New Physics,” meaning new elementary particles and new interactions that extend our understanding. We can summarize the search for New Physics in three categories: the search for new elementary particles; the search for dark matter; and the measurement of the Higgs boson’s properties.

New elementary particles are predicted by exotic theories, such as supersymmetry or extra dimensions, but have never been observed.

Dark matter particles, which make up 85 percent of the mass of the universe and have never been observed in the lab, can be produced in high-energy proton-proton collisions at the LHC. Seeing them for the first time would be a revolutionary achievement.


Watch this video about the Sciolla Lab’s hunt for dark matter


New interactions and new particles will affect the behavior of the Higgs boson. For example, the Higgs will interact with other particles in a way that is different from what the current theory predicts.

What are you most excited about?

Difficult choice! These three avenues are all very promising and may all lead to a paradigm shift in physics. However, choices need to be made since we cannot work on each and every topic.

At the very beginning of Run 2, my group will focus on two topics: extra dimensions and dark matter. Theories of extra dimensions predict a new particle, known as Graviton, that decays into two energetic elementary particles called muons. Given our know-how in muon reconstruction, it is natural for my group to lead these searches.

This experiment costs an awful lot of money. What do you tell people who question its value?

It’s hard to put a price tag on knowledge. This experiment gives us a chance to understand how the universe works at its most fundamental level. The technological applications we develop in pursuit of scientific answers are important. But understanding the basic science will benefit humanity in the long term.

The LHC experiments are international projects, so we share the costs. The ATLAS experiment, for example, was built by a collaboration of 38 countries on four continents.

What will you be thinking when the experiment officially restarts?

It will certainly be a historic moment. These collisions could change the way we think about particle physics. Since I am responsible for the reconstruction and calibration of muons in the ATLAS experiment, I will be totally absorbed in delivering the best quality muons to the collaboration. Muons are crucial ingredients for many searches for New Physics.

If the accelerator works as expected, we need only a few months of data to publish our first results. We can’t wait!

Researchers identify potential cause of schizophrenic symptoms

Imagine a waking nightmare.

That’s how Elyn Saks, law professor and mental health advocate, describes the delusions, hallucinations, memory loss and mental fragmentation that schizophrenia causes.

The mental disorder affects millions of people worldwide but the cause of its wide-ranging symptoms remains largely unknown.

At Brandeis University, researchers believe they have discovered an abnormality in the schizophrenic brain that could be responsible for many of the disease’s symptoms and could provide a drug target for therapeutic treatments.

John Lisman photo/Mike Lovett
John Lisman photo/Mike Lovett

Led by John Lisman, the Zalman Abraham Kekst Chair in Neuroscience and professor of biology, and Matthew Wilson of MIT, the research team published their findings in a recent issue of the Journal of Biological Psychiatry. The paper was co-authored by Aranda Duan, Carmen Varela, Yuchun Zhang, Yinghua Shen, Lealia Xiong, and Matthew Wilson.

Unusual neural oscillations — brain waves — have long been associated with schizophrenia. The oscillations, called delta waves, are similar to slow oscillations seen in normal brains during sleep, but in schizophrenic brains, they occur during wakefulness. The connection between these oscillations and schizophrenic symptoms, particularly cognitive deficits such as memory impairment, has long been unclear.

Lisman and his team set out to understand that connection by artificially producing delta waves in mammalian brains using a new technique called optogenetics, which activates brain signals using light.

When the delta frequency light was turned on, Lisman observed disruption in the working memory of rats. When it was turned off, the rodents were once again able to perform working memory tasks. More important, Lisman and his team were able activate the abnormal oscillations only in a tiny subpart of the thalamus, a region of the brain that has long been a focus of schizophrenia research.

An information hub and relay center, the thalamus is central to working memory, sleep, consciousness and sensory-information processing.

“The oscillations produce an artificial signal that jams normal communication,” Lisman says. “The part of the thalamus that is supposed to carry information about working memory couldn’t do the task at all with these sleep-like delta waves. We suspect the abnormal delta oscillations seen in patients with schizophrenia are producing a similar jamming of normal signals.”

The green axons of thalamic neurons can be seen as they innervate the hippocampus. It is these axons, when stimulated by light, that jam communication. Courtesy/Lisman Lab
The green axons of thalamic neurons can be seen as they innervate the hippocampus. It is these axons, when stimulated by light, that jam communication. Courtesy/Lisman Lab

Delta waves require a specific type of ion channel called a T-type Ca channel. These channels are of particular interest because they are one of the few types of ion channel implicated in schizophrenia by genetic studies. The next step, Lisman says, is to figure out what kind of agents could be used to block these channels.

“If you could block these channels, you could block these bad oscillations,” he says. “That may have therapeutic value in patients.”

Birds, bees and the nature of space

Ever wonder what theoretical physicists actually do? In honor of the 100th anniversary of Albert Einstein’s theory of general relativity, ReAction is sitting down with theoretical physicists at Brandeis to find out.

Theoretical physics is a lot like sex, Nobelist Richard Feynman once quipped. “Sure, it may give some practical results, but that’s not why we do it.”

The prevailing stereotype outside — and inside — the sciences is that theoretical physicists have their gaze firmly fixed on their navels and play in a sandbox of their own creation.

It’s time to throw that stereotype out the window (and note how it falls to Earth with constant acceleration. Thanks, theoretical physics!)

Sure, theoretical physics can get weird, and some theories are pretty far out, but inquiry is always driven by a hunger to understand the universe fundamentally.

Consider Brandeis’ High Energy and Gravitational Theory Group.

These physicists research bizarre principles like holography, which postulates that all the information in the universe is stored on a two-dimensional surface, and we are mere projections of that information. And then there’s quantum entanglement, which even Einstein called “spooky.”

But at the core of the group’s research is a simple question: What is space?

Einstein described the way space is connected to time and how it interacts with mass. But he never theorized what space is, how it’s formed or what it’s made of.

Einstein's general relativity reimagined gravity not as force, as Newton described it, but as space curved by matter, through which matter travels.
General relativity reimagined gravity not as force, as Newton described it, but as space curved by matter. Courtesy/NASA

“Since Einstein, our questions have gotten bigger and deeper,” says Matthew Headrick, assistant professor of physics. “We want to figure out the nature of space.”

The answer lies somewhere between two pillars of modern theoretical physics — general relativity ( GR, which describes gravity) and quantum field theory ( QFT, which describes, among other things, particle physics). These fundamental theories describe two very different aspects of our universe and are written in different mathematical languages.

Watch this video for an overview of QFT and GR

“Shockingly, in certain cases, theorists have discovered that these two very different theories are actually secretly the same,” Headrick says. “Between GR and QFT, there is some kind of one-to-one map. We know some of the shared points but we’re still in the dark about many others.”

This one-to-one map is holography and it represents GR, which lives in ordinary three-dimensional space, by a QFT living on a two-dimensional surface — just like a hologram.

Essentially, Headrick and other theoretical physicists are building a Rosetta Stone —a bilingual dictionary of sorts — using holography, general relativity and quantum field theory. This translational tool will expose how GR and QFT are connected to each other and how to build a new language that obeys the properties of both GR and QFT.

Word by word, Headrick and his colleagues are testing and building a framework of conjectures.

“If you have confidence that a conjecture obeys the properties it needs to obey, you can enter it into the dictionary,” Headrick says. “Each small entry tells us something more about space.”

One conjecture Brandeis theorists pioneered has to do with the relationship between the geometry of space and the quantum information it contains.

Mathematically, certain areas in curved space contain minimal surfaces — a surface that minimizes its area. Dip a wand into soapy water and the soap film will stretch perfectly flat across the shape of the wand. This is a minimal surface.

Bubble Wand

“If the area of that soap film is expressed in fundamental units, it tells us about the quantum entanglement in the QFT,” says Headrick.

In other words, Headrick and his colleagues use the mathematical language of general relativity — geometry — to extrapolate a quantum property. That calculation, in turn, provides new information about how the two languages are interconnected.

That idea also provides a clue to the nature of space.

“It suggests that, fundamentally, the space that we live in and take for granted is stitched together out of quantum entanglement,” Headrick says.

Watch this video for an overview of entanglement

The next step is to figure out why.

The answers to these and other questions will, with any luck, give researchers the words and syntax to compose a theory of gravity in the language of quantum mechanics. It’s the Holy Grail of modern theoretical physics: a theory of quantum gravity.

But what does this have to do with reality? Richard Feynman may not have cared about the practical results of theoretical physics, but some do.

Be patient, Headrick says.

It took Einstein 10 years to develop general relativity, and it took physicists another 40 years to understand the black holes it predicted. Now, 100 years after the theory’s publication, relativity is ubiquitous in our daily lives. Without an understanding of it, for example, we wouldn’t have GPS.

But more important than the inventions a theory spurs, is the knowledge a theory advances, Headrick says.

“Einstein, Feynman and others profoundly changed our understanding of nature,” he says.

And that’s why theoretical physicists do it.

 

Special thanks to Cesar Agón for helping in the development of this story. 

We Are Brandeis Science: Hannah Herde

There is no rule that says scientists have to look or act a certain way. Scientists can be funny and outgoing, athletic and artistic. They come from all different backgrounds and have all different interests. Who are the people behind the groundbreaking research at Brandeis University? We Are Brandeis Science aims to find out. This on-going series is inspired by This is What a Scientist Looks Like

This post was written by physics PhD candidate Hannah Herde.

 A mind-blowing mystery

 Where are you from?

That’s a complicated question. I was born in Washington, D.C. but lived in New Canaan, Conn., for most of my life. My family moved to London during my middle school years, where Britain’s dedication to science education certainly helped me to develop my passion.

What do you research?

Herde in front of the Globe of Science at CERN
Herde in front of the Globe of Science at CERN

I work with physics professor Gabriella Sciolla on the search for dark matter, one of the greatest mysteries of the universe. As it turns out, dark matter accounts for 85 percent of the mass of the universe — which blows my mind. I would very much like to find out what most of the universe is made of, and how these materials interact with the matter out of which you and I, the stars, and everything else we perceive, is made.

As a kid, what did you want to be when you grew up?

When I was 8 years old, I wanted to be an oceanographer — I wanted more than anything else to probe the fathoms of the sea. That was my dream for nearly a decade and during high school, I worked more than 300 hours at The Maritime Aquarium in Norwalk, Conn. Through my experience there, I learned that I wanted to understand more than just what is out there — I wanted to understand how everything works and why it came to be that way. As I continued my education, I came to feel that those questions were best answered through physics.

What got you into science?

Dirt. Good old-fashioned digging in the dirt. I was very fortunate growing up — my parents made sure that my three siblings and I always had a yard in which to play. Pill bugs, rocks, flowers, frogs — just about anything I could find in the yard rapidly transformed into an experiment.

What’s the coolest place you’ve ever been?

CERN’s Large Hadron Collider, 150 meters underground at the ATLAS detector. It is enormous!

Guest post: We need a super agenda to tackle superbugs

This article was written by Moaven Razavi, Senior Research Associate in the Schneider Institutes for Health Policy at the Heller School of Brandeis University.  It was originally published on Heller News

Drug resistant infections are turning into the biggest challenge that modern health systems will face in the near future. Statistics and estimates are breathtaking: by 2050, such infections are estimated to kill 10 million people per year. To put it in context, this is higher than the current global burden of cancer.

Today, there are 700,000 cases of drug resistant infections annually— and this is not just a problem for developing nations. In Europe and the U.S., these infections are already killing more than 50,000 people each year. If our response remains status quo, we would see the death toll rise more than 10 times by 2050, and the economic cost would spiral to $100 trillion.

The true gravity of the threat is being seriously examined in Europe. In July 2014, British Prime Minister David Cameron warned that we are in danger of being “cast back into the dark ages of medicine” if we fail to act, and announced an internationally focused review to address the problem. The taskforce was charged with developing a package of actionable recommendations in response to antimicrobial resistance (AMR) by the summer of 2016.

In the United States, however, the reaction to the problem has been sporadic and limited in scope. In January 2015, Senators Orrin Hatch (R-Utah) and Michael Bennet (D-Colo.) reintroduced legislation to accelerate the approval of new antibiotics to address drug-resistant “superbugs.” The bill, known as the PATH Act, would allow the FDA to expedite approval processes for novel medications.

While the U.S. Senate bill is tied to the threat that AMR poses to U.S. troops returning from Iraq and Afghanistan, the biggest risk is to senior citizens due to two major factors: the need for more invasive surgeries such as major joint replacements and heart surgeries, and the weakened immune system due to aging. The elevated risk level due to AMR poses a serious challenge to solvency of the Medicare program.

Even though the threat to the Medicare population is looming, the extent of the problem is not well assessed. Globally, the reliable estimates are scarce, and there is considerable variation in the patterns of AMR. However, drug resistant infections are a problem that should concern every country regardless of geography or income. According to the European Centre for Disease Prevention and Control’s Antimicrobial Resistance Interactive Database, in 2013, 15 European countries saw more than 10 percent of their bloodstream Staphylococcus aureus infections caused by methicillin-resistant strains (MRSA), with several of these countries seeing resistance rates closer to 50 percent.

Recognizing the severity of this issue, I joined several of my colleagues from the Institute on Healthcare Systems in investigating just how severely AMR is threatening the Medicare population. The study, which was funded by GlaxoSmithKline Pharmaceuticals (GSK), focused on Staphylococcus aureus (S. aureus), which is by far the most dangerous superbug. We examined the incidence of S. aureus infections following 219,958 major surgical procedures for a representative 5 percent sample of Medicare beneficiaries from 2004 to 2007.

We found that 0.3 percent of these patients had S. aureus infections immediately following their surgical procedures, while 1.7 percent were hospitalized with S. aureus infections within 60 days and 2.3 percent were hospitalized with S. aureus infections within 180 days. S. aureus infections within 180 days were most prevalent following gastric or esophageal surgery, with 5.9 percent of patients affected, followed by hip surgery (2.3 percent), and coronary artery bypass graft surgery (1.9 percent).

Of patients hospitalized with a major infection during the first 180 days after surgery, 15 percent of those infections were due to S. aureus, 18 percent were other documented organisms, and no specific organism was reported in 67 percent. We also found that infections prolonged the length of hospitalization by 130 percent, and S. aureus infection was associated with a 42 percent excess risk of mortality.

Due to incomplete documentation of organisms in Medicare claims, these statistics may underestimate the true magnitude of S. aureus infection; nevertheless, this study found a higher rate of S. aureus infections than previous investigations.

I believe that tackling the superbug crisis requires a super-agenda—one that involves both public and private stakeholders who are informed by solid research in a timely manner. Such an agenda should not only include promotion of research and investment in new drugs and treatment modalities, but also prevention measures in all domains. The role of Medicare and commercial payers is also critical and can be incorporated through payment reforms, value based purchasing efforts, and introduction of relevant re-admission and complication quality indicators.

Moaven Razavi is the lead author of the study, Postoperative Staphylococcus aureus Infections in Medicare Beneficiaries, which was published in the November 2014 edition of PLoS ONE. Other researchers include Donald S. Shepard and William B. Stason from Heller, and Jose A. Suaya form GlaxoSmithKline. 

Enter Sandwoman

Let’s put winter behind us — it’s time to think about sand.

Physicists think about sand a lot because they don’t really understand how it works. How can sand — and other granular materials such as grains or rocks — behave both like a liquid that flows through fingers and a solid that forms dunes?

Physicists have a theoretical framework to predict how microscope objects like molecules flow and freeze but lack the fundamental concepts to describe how assemblies of macroscopic objects behave similarly.

Last year, Bulbul Chakraborty, the Enid and Nate Ancell Professor of Physics received a three-year, $1 million grant from the W.M. Keck Foundation to develop the first predictive theoretical framework to characterize the collective behavior of a large number of macroscopic objects.

BulbulSand
This theoretical representation of experimental data (Behringer Lab.) provides a quantitative tool for identifying the fluid to solid transition in a granular solid. The fluctuations in the net show the change in strength of the solid. Credit: Sumantra Sarkar, Brandeis University

She and her team are developing quantitative tools for identifying the fluid to solid transition in granular solids in order to build a theoretical framework to describe assemblies of macroscopic objects.

Here is a peak inside her lab.

Chill out! You control your stress response

Think finals are stressful? Try being chased by a lion.

Humans evolved in a dangerous, threatening world where stress usually preceded bodily injury. As a result, the evolutionary theory goes, our stress response system jump-starts our immune system, triggering the deployment of white blood cells and increased expression of the inflammatory gene interleukin-6 (IL-6) into the blood stream.

As part of our immune system, IL-6 can help stave off infection and promote wound healing, but if left unregulated, this inflammatory agent can contribute to cardiovascular disease, cancer and Alzheimer’s. Knowing where and how in the body various forms of IL-6 are produced is an important step in understanding how stress relates to disease.

In a recent study published in Brain, Behavior and Immunity, Brandeis researchers discovered that one’s perception of stress directly impacts how genes express stress. The paper was written by graduate student Christine McInnis and professor Nicolas Rohleder, and co-authored by Danielle Gianferante, Luke Hanlin, Xuejie Chen and Myriam Thoma.

Researchers have long known that IL-6 proteins increase in blood plasma after stress but this is the first time scientists have observed increased activation of the IL-6 gene in white blood cells as a stress response.

The size and duration of the increase is closely tied to perception and mood, according to the study. The more a person stresses out, the more IL-6 is expressed.

“Stress perception initiates the gene expression and self-reported mood changes are directly related to the size of the gene expression response,” says McInnis.

In other words, we can, to some extent, control our genetic response to stress by moderating how we perceive stress.

“If you learn to control your stress levels, your genes will follow,” says McInnis.

So next time you’re stressed about a big test, calm down: It might be a bear of a test, but it’s no lion.

This research was supported by the American Federation of Aging Research. 

Science friction: Unlocking this basic force may lead to futuristic technologies

Here’s the rub with friction — scientists don’t really know how it works. Sure, humans have been harnessing the power of friction since rubbing two sticks together to build the first fire, but the physics of friction remains largely in the dark.

Ancient Egyptians used friction
Ancient Egyptians understood friction well enough to know that heavy objects moved easier across wet sand than dry sand, as can be seen in this picture.

In a new paper in Nature Materials, Brandeis University professor Zvonimir Dogic and his lab explored friction at the microscopic level. They discovered that the frictional force is much stronger than previously thought. The discovery is an important step toward understanding the physics of the cellular and molecular world and designing the next generation of microscopic and nanotechnologies.

The research was conducted as part of the Brandeis University Materials Research Science and Engineering Center.

Dogic and his team focused on the frictional forces of actin filaments, essential cellular building blocks responsible for many biological functions including muscle contraction, cell movement and cell division. All of these processes require filaments to move and slide against one another, generating friction.

Actin filament experiment
A schematic of the experimental set-up. Actin filaments attached to gelsolin-coated beads are assembled into anti-parallel bundles using optical traps. Bead 2 is pulled at a constant velocity while simultaneously measuring the force exerted on bead.

Scientists assumed that the frictional forces of these movements were minimal, acting more like weaker hydrodynamic friction — like pulling an object through water — than the larger solid friction — pushing an object across a desk.

But Dogic and his team observed the opposite. They developed a new technique to measure friction, and when they dragged two actin filaments against each other, they observed frictional forces nearly 1,000 times greater than expected — closer to solid friction than hydrodynamic friction.

This is due, in part, to interfilament interaction. Imagine filaments as two beaded strings, one on top of the other, pulled in opposite directions. As the strings move, the beads must go up and over their counterparts on the opposite string, generating even more friction. By observing this interfilament interaction, Dogic and his team were able to measure the frictional forces and tune them, altering the forces to include more or less friction.

“Before this research, we didn’t have a good way of controlling or understanding friction,” Dogic says. “We still have a lot more to understand but now, one of our oldest sciences is becoming less opaque.”

The paper was coauthored by Brandeis scientists Andrew Ward, Fiodar Hilitski, Walter Schwenger and David Welch; A. W. C. Lau of Florida Atlantic University; Vincenzo Vitelli of the University of Leiden, and L. Mahadevan of Harvard University.

This research was funded by the National Science Foundation.